Fluid pressure at the well head generally ranges from 200 to 5000 pounds per square inch and is generally reduced to a pressure of 1000 pounds per square inch or less by delivering the fluid through a choke before the fluid enters a pipe line to a storage tank. A typical choke comprises a flow passage with a fixed diameter or one in which the flow passage may be varied by turning a valve. Significant refrigeration or cooling of the fluid occurs when the fluid at 5000 pounds per square inch passes through an orifice in the choke and expands into the line at 1000 pounds per square inch. The resultant refrigeration causes formation of frost on the surface of the pipe line and may result in freezing the fluid within the pipe line thereby blocking the passage of the fluid through the line.
Heretofore, heaters have been employed to transfer heat to the fluid which is passed through the choke. Heretofore, a portion of the gas or oil produced by the well has been burned to heat air in a heat exchanger formed around the choke or pipe line.
Burning of fuel gas or oil from the well for heating fluid produced by the well in some instances results in consumption of significant percentages of the fuel produced by the well. It is often necessary to provide a source of gas, for example butane, for heating liquid to separate water from oil if an insignificant volume of gas is produced by the well to provide the required heat. This results in waste of that portion of gas which is burned to heat the pipe line or results in a costly expenditure to provide other hydrocarbon type fuels for heating the liquid for separation of the fluid produced or for heating to prevent freezing.
Wells generally produce an emulsion of oil, gas and water and various other liquids which are very corrosive in nature. Before introduction of the fluid into the pipe line, it is desirable to separate the gas and water from the oil. An emulsion separator is often used comprising a holding tank. The emulsion is delivered into the upper portion of the tank and a heater is positioned below the tank to heat the emulsion. The heat causes the gas to boil off and the gas is piped off at the top. Warm oil will float to the top while the water goes to the bottom. The oil is syphoned off and the water is drained off of the bottom. Heretofore these devices have utilized gas or oil burners which have consumed a portion of the gas or oil from the well or must be supplemented with butane and, therefore, consumes more of the fuel being produced.